## Step-by-Step Solution ### **Understanding Rule #1 (Perfect Form at MMC)** Rule #1 in GD&T (Geometric Dimensioning and Tolerancing), also known as the "Envelope Principle," states: - A feature of size must have perfect form at Maximum Material Condition (MMC). - This means: at the largest allowed material condition, the feature must be perfectly straight, flat, round, etc. **Rule #1 can be overridden** in some cases, such as: - By using the Independency symbol (⏊). - By using specific notes. - By applying certain geometric controls. --- ### **Analyzing Each Option** #### **Option 1:** > When a straightness control is applied to a feature of size. - **Explanation:** Applying a straightness control to a feature of size *at MMC* can override Rule #1 by allowing deviations in form beyond perfect form at MMC. - **Is this a way to override Rule #1?** **Yes, it is.** --- #### **Option 2:** > When a note, such as "NON-RIGID FEATURE - PERFECT FORM AT MMC IS NOT REQUIRED", is added to the drawing. - **Explanation:** This note *explicitly* states that perfect form at MMC is **not required**, which directly overrides Rule #1. - **Is this a way to override Rule #1?** **Yes, it is.** --- #### **Option 3:** > When the Independency symbol is placed next to the applicable feature control frame. - **Explanation:** The Independency symbol (⏊) tells us that the feature does *not* have to follow Rule #1, thus overriding the envelope principle. - **Is this a way to override Rule #1?** **Yes, it is.** --- #### **Option 4:** > When a flatness control is applied to a feature of size. - **Explanation:** Applying a flatness control to a feature of size overrides Rule #1 by allowing flatness deviation even at MMC. - **Is this a way to override Rule #1?** **Yes, it is.** --- #### **Option 5:** > When the surface straightness tolerance listed is larger than the size tolerance. - **Explanation:** Rule #1 says perfect form at MMC is required, and form deviation cannot exceed the size tolerance. If the surface straightness tolerance is *larger* than the size tolerance, it does **not** override Rule #1 — it's simply incorrect or redundant, as the size tolerance already restricts form. - **Is this a way to override Rule #1?** **NO, this does NOT override Rule #1.** --- ## **Final Answer** ### **The correct answer is:** > **When the surface straightness tolerance listed is larger than the size tolerance.** --- ## **Summary Table** | Option | Overrides Rule #1? | Explanation | |--------|--------------------|-------------| | 1. Straightness control on feature of size | **Yes** | Overrides rule by specifying form tolerance | | 2. Note: "PERFECT FORM AT MMC IS NOT REQUIRED" | **Yes** | Explicitly overrides Rule #1 | | 3. Independency symbol | **Yes** | Overrides envelope requirement | | 4. Flatness control on feature of size | **Yes** | Overrides rule by specifying flatness tolerance | | 5. Surface straightness tolerance > size tolerance | **No** | Does NOT override Rule #1 | ### **Incorrect Options Explained:** - Options 1, 2, 3, and 4 all provide explicit means to override Rule #1 by GD&T standards. - Option 5 does NOT override Rule #1; it is either redundant or results in an impossible scenario according to the envelope principle. --- **If you need more examples or visual explanations, let me know!**